Glass safety syringe and relative safety kit for glass syringe

ABSTRACT

A safety syringe includes a glass syringe body, a plunger slidable inside the syringe body and provided at the rear with a manually operable stem, an injection needle mounted at the front end of the syringe body, a sheath mounted integrally on the syringe body, a sleeve mounted slidably on the sheath to pass from a retracted use position to an advanced safety position, in which the needle is protected by the sleeve, locking elements mutually provided in the sheath and in the sleeve to lock the sleeve in position when it is in the retracted use position and in the forward safety position, and operating elements integrally mounted with the stem of the piston to cooperate with locking elements so as to allow movement of the sleeve from the retracted use position to the advanced safety position.

The present invention refers to a glass syringe, of the disposable type,provided with an automatic safety device to protect the needle once theinjection has been preformed. The present invention also refers to arelative safety kit that can be applied to a disposable glass syringe.

A syringe generally comprises a cylindrical body open at the rear toreceive a plunger. An internally hollow needle is mounted at the head ofthe syringe body.

Because of health regulations and to avoid transmission of infectiousdiseases, syringes must generally be used only once and then discarded.For this reason, there is a growing demand for disposable syringesadapted to prevent further use.

Moreover, syringes generally present drawbacks from the point of view ofsafety. In fact, once the syringe has been used, the needle remainsexposed at the head of the syringe body, with the risk of injuries oraccidental needle sticks.

To overcome these drawbacks, plastic disposable syringes having safetydevices to cover the needle are available on the market.

Patent application PCT WO 99/37345 describes a disposable safety syringewhich has a needle covering sleeve mounted axially on the syringe bodyand slidable from a retracted position in which it leaves the needleexposed to allow injection, to an extended position in which itcompletely covers the needle, preventing re-use of the syringe andacting as a protection against accidental needle sticks.

Once the injection has been performed, the sleeve is automaticallybrought into the extracted safety position, by means of an automaticmechanism and without any intervention by the user.

Glass syringes, on the other hand, are generally designed to be able tobe reused. In fact, the glass syringe body can be sterilized at hightemperature. For this reason, glass syringes generally do not provideany safety device for protection of the needle once the injection hasbeen performed.

As is known, prefilled syringes in which the solution is already insidethe barrel of the syringe, ready for injection, are widely available onthe market. However, there exist some solutions such as vaccines,antidotes and the like which cannot be stored in plastic containers.Consequently, said solutions must necessarily be placed in prefilledglass syringes.

For this reason and for reasons of hygiene and practicality, glasssyringes of the disposable type exist on the market. Disposable glasssyringes have the drawback of not having a safety device for protectionof the needle.

An object of the present invention is to eliminate the prior artdrawbacks providing a glass safety syringe that is practical, versatile,economical and simple to make.

Another object of the present invention is to provide such a glasssafety syringe of the disposable type that is able to prevent furtherattempts at use.

Another object of the present invention is to provide such a glasssyringe that is extremely safe and able to prevent accidental injury andtampering after use.

These objects are achieved in accordance with the invention with thecharacteristics listed in appended independent claim 1.

Advantageous embodiments of the invention are apparent from thedependent claims.

The syringe according to the invention comprises a glass syringe bodyhollow on the inside and open at the front and the rear, a plungerslidable inside the syringe body and provided at the rear with amanually operable stem and an injection needle mounted at the fore endof the syringe body.

To make this syringe a safety syringe according to the invention, asheath integrally mounted on the glass syringe body and a sleeveslidably mounted on the sheath to pass from a retracted use position inwhich the needle protrudes forward from the sleeve to be able to performthe injection to an advanced safety position in which the needle isprotected by the sleeve.

Locking means and stops are provided reciprocally in the sheath andsleeve such as to lock sleeve in position when it is in the retracteduse position and in the advanced safety position. Operating means ableto cooperate with the locking means when the plunger is at the end ofthe injection stroke are fitted to the rear part of the piston stem, toallow the sleeve to be moved from the retracted use position to theadvanced safety position.

The advantages of the syringe according to the invention are obvious inthat it allows a glass syringe to be made into a safety syringe, byproviding the possibility of covering the needle with the sleeve oncethe injection has been performed.

Further characteristics of the invention will be made clearer by thedetailed description that follows, referring to a purely exemplary andtherefore unrestrictive embodiment thereof, illustrated in the appendeddrawings, in which:

FIG. 1 is a top plan view of the safety syringe according to theinvention, in the position ready for use, with a needle-covering capmounted at the head of the syringe body;

FIG. 2 is an axial sectional view of the safety syringe of FIG. 1, inwhich the syringe body and the piston stem are shown in side view;

FIG. 3 is an axial sectional view taken along the sectional planeIII-III of FIG. 1, in which the piston stem is shown in side view and inthe end of injection position and the needle-covering cap has beenremoved;

FIG. 4 is an axial sectional view, like FIG. 3, in which the needle isin the safety position;

FIG. 5 is a perspective view, illustrating a sheath for covering asyringe body.

The safety syringe according to the invention, denoted as a whole byreference numeral 100, is described with the aid of the figures.

The syringe 100 comprises a syringe body 1 (shown in FIGS. 2 and 4) madeof glass. The syringe body 1 is substantially cylindrical in shape, ishollow on the inside and has a cylindrical chamber open at the front andrear. The body 1 has at its fore end a head 10 into which a needle 11 issunk. The body 1 has at its rear end a flange 12 that protrudes radiallytherefrom to facilitate gripping by the user.

As shown in FIG. 3, a plunger 2 made of rubber can slide axially with atight seal in the cylindrical chamber of the syringe body 1. The plunger2 is supported at the fore end by a stem 20 made of glass or plastic.The stem 20 has at its rear end a flange 21 disposed on the outside ofthe syringe body 1 to be able to be operated manually by the user.

In the rear part of the stem 20 a frusto conical block 22, disposedaround the stem 20, near the flange 21 of the stem, is provided. Thefrusto conical block 22 has a tapered side surface with a diameter thatincreases toward the rear part of the stem 20.

The frusto conical block 22 can be formed integrally in the rear part ofthe stem, or it can be a separate element to apply to the stern 20. Inthis latter case, the frusto conical block 22 has an axial hole 24 to beforcibly inserted, from the front part of the stem, until it abutsagainst the rear flange 21 of the stem. In this case, the frusto conicalblock 22 has an annular groove 23 to be able to yield elastically.

A tubular sheath 3 that almost entirely covers the side surface of thesyringe body 1 is mounted on the syringe body 1. As shown also in FIG.5, the sheath 3 comprises at its fore end a collar 30 which protrudesradially outward so as to define an annular abutment surface 35.

Two teeth 31 that protrude radially outward in diametrically oppositedirections are provided on the collar 30. Two longitudinal slots 32disposed in diametrically opposite positions are provided on the sidesurface of the sheath 3, level with the teeth 31. In this manner, eachlongitudinal slot 32 defines a rear abutment surface 33 and a frontabutment surface 34.

The sheath 3 is made of plastic material and is elastically forced andfixed on the glass body 1. The syringe body 1, with the sheath 3integral therewith, is mounted axially slidably inside a substantiallycylindrical sleeve 4, hollow on the inside. In this manner, the head 10of the syringe body 1 protrudes forwardly and axially from the sleeve 4and a needle-covering cap 8 is fitted to the head 10.

The sleeve 4 has a cylindrical rear part 40 with a greater diameter anda cylindrical front part 41 with a smaller diameter, so as to define onthe inside an annular abutment surface 42. In this manner, as shown inFIG. 2, a helicoidal compression spring 6 which winds around the sheath3 is interposed between the annular abutment surface 35 of the collar 30of the sheath 3 and the annular abutment surface 42 of the sleeve 4.

As better shown in FIG. 1, two rear tongues 43 are formed in the sidewall of the part 40 of the sheath with the largest diameter. The reartongues 43 are disposed longitudinally in diametrically oppositepositions and are flexible. Each rear tongue 43 has a rectangular slot44 within which the respective tooth 31 of the collar 30 of the sheathsnap engages, so as to firmly retain the sheath 3 inside the sleeve 4.

Each rear tongue 43 is defined by two longitudinal parallel notches 45which reach the end of the part with the greatest diameter 40. In thismanner, each rear tongue 43 can bend radially outward. Furthermore, eachrear tongue 43 has a rear part which protrudes rearward beyond the rearend of the part with the largest diameter, 40. The rear end of eachtongue 43 has a tapered surface 46 able to cooperate with the taperedsurface of the frusto conical block 22 of the stem.

At the rear end of the part with the greater diameter 40, a flange 55protrudes radially to facilitate gripping by the user. The rear flange55 of the sleeve is not present in the area in which there are the reartongues 43 so as not to interfere therewith. The flange 55 of the sleevehas in its rear wall an annular abutment surface against which the rearflange 12 of the glass body 1 abuts.

In the lateral part of the part with the smallest diameter 41 of thesleeve two central tongues 47 are formed. The central tongues 47 aredisposed longitudinally in diametrically opposite positions and areflexible. Each central tongue 47 is defined by a substantially U-shapednotch 48, so as to be able to bend radially outward.

Each central tongue 47 has an inwardly protruding tooth 49 able toengage in the respective longitudinal slot 32 of the sheath 3. In thismanner, when the syringe body 1 with the sheath 3 are inserted insidethe sleeve 4, the central tongues 47 are widened and then elasticallysnap back when the teeth 49 engage in the respective slots 32 in thesheath.

Two front tongues 50 are formed in the side wall of the sleeve part 41with the smallest diameter. The front tongues 50 are longitudinallydisposed in diametrically opposite positions. Each front tongue 50 isdefined by a substantially U-shaped notch 51, so as to be able to bendradially outward. Under normal conditions, each front tongue 50converges inwardly and has at its front end an abutment surface 52.

Operation of the syringe 100 according to the invention will now bedescribed.

With reference to FIGS. 1 and 2, in an initial condition the spring 6 iscompressed between the annular abutment surface 35 of the collar 30 ofthe sheath 3 and the annular abutment surface 42 of the sleeve 4. Theteeth 32 of the sheath are engaged in the slots 44 of the rear tongues43 of the sleeve avoiding any axial movement of the sheath 2 and body 1assembly with respect to the sleeve 4. Furthermore, the teeth 49 of thecentral tongues 47 are in abutment against the front abutment surface 33of the longitudinal slot 32 of the sheath, avoiding any axial rearwardmovement of the sheath 3 with respect to the sleeve 4.

The chamber of the body 1 is pre-filled with a solution to be injected.Thus, when the injection is performed and the plunger 2 reaches the endof its stroke in the chamber of the syringe body, as shown in FIG. 3,the tapered surface of the frusto conical block 22 cooperates with thetapered surface of the rear end 46 of the rear tongues 43, causingoutward radial bending thereof.

Consequently, the teeth 31 of the sheath 3 disengage from the slots 44of the tongues 43 and the sleeve 4 is no longer firmly constrained tothe sheath 3 and syringe body 1 assembly. As a result, as shown in FIG.4, the spring 6 which was compressed is released, lengthening andcausing axial forward sliding of the sleeve 4 with respect to the sheathand syringe body assembly, until the teeth 49 of the central tongues 47of the sleeve abut against the respective rear abutment surfaces 34 ofthe longitudinal slots 32 of the sheath.

Said axial movement of the sleeve 4 with respect to the sheath andsyringe body assembly is guided, since the teeth 49 of the centraltongues 47 of the sleeve slide in the respective longitudinal slots 32of the sheath. Furthermore, when the rear end 52 of the front tongues 50of the sleeve passes the front end of the sheath 3, the front tongues 50converge elastically inward.

In this situation, the needle 11 is protected in the safety positioninside the sleeve 4. It should be noted that when the syringe 100 is inthe safety position, any axial movement of the sleeve 4 with respect tothe sheath and syringe body assembly is prevented. In fact, the frontend of the sheath 3 abuts against the rear end 52 of the front tongues50 which are convergent and the rear abutment surfaces 34 of the slots32 in the sheath are in abutment against the respective teeth 49 of thecentral tongues 47 of the sleeve.

It is evident that the present invention, besides referring to thesafety syringe 100 as described, also refers to a safety kit comprisingthe sheath 3, the spring 6, the sleeve 4 and the frusto conical block22, considered as separate pieces which are applied to a glass syringeof the known type to make it a safety syringe.

Numerous variations and changes of detail within the reach of a personskilled in the art can be made to the present embodiment of theinvention, without thereby departing firm the scope of the invention asset forth in the appended claims.

1-10. (canceled)
 11. A safety syringe (100) comprising: a glass syringebody (1) hollow on the inside and open at the front and rear, a plunger(2) slidable inside the syringe body (1), said plunger being provided atthe rear with a manually operable stem (20) brought out of the syringebody by means of the rear end (21) thereof, and an injection needle (11)mounted at the front end (10) of the syringe body (1), characterized inthat it comprises: a sheath (3) integrally mounted on said glass syringebody (1), a sleeve (4) slidably mounted on said sheath to pass from aretracted use position in which the needle (11) protrudes forward fromsaid sleeve to be able to perform the injection to an advanced safetyposition in which the needle (11) is protected by said sleeve (4),locking and stop means, mutually provided in said sheath and in saidsleeve to lock said sleeve (4) in position when it is in said retracteduse position and said advanced safety position, and operating means (22)integrally mounted to the rear part of the plunger stem (20) tocooperate with said locking means, when the plunger (2) is at the end ofthe injection stroke to allow movement of said sleeve (4) from theretracted use position to the advanced safety position.
 12. A safetysyringe (100) according to claim 11, wherein it comprises spring means(6) interposed between said sleeve (4) and said sheath (3).
 13. A safetysyringe (100) according to claim 12, wherein one end of said springmeans is in abutment against an annular abutment surface (42) definedbetween a larger diameter part (40) and a smaller diameter part (41) ofsaid sleeve and the other end of said spring means is in abutmentagainst an annular abutment surface (35) defined by a collar (30)protruding outward at the fore end of said sheath (3).
 14. A safetysyringe (100) according to claim 12, wherein said locking means comprisetwo teeth (31) radially protruding from said sheath, in diametricallyopposite directions, to engage in respective slots (44) provided in tworear elastic tongues (43) longitudinally formed in the rear part of theside wall of said sleeve (4).
 15. A safety syringe (100) according toclaim 14, wherein each of said rear tongues (43) is defined by twolongitudinal parallel notches formed in said side wall of the sleeve, upto the rear end of the sleeve, and the rear end of said tongues (43)protrudes radially beyond the rear end of the sleeve.
 16. A safetysyringe (100) according to claim 14, wherein said operating meanscomprise a frusto conical block (22) cooperating with said rear tongues(43), when the plunger (2) reaches the end of the injection stroke, inorder to make them diverge outward to disengage said teeth (31) of thesheath from said slots (44) of the rear tongues.
 17. A safety syringe(100) according to claim 12, wherein said stop means comprise a pair offlexible central tongues (47), longitudinally provided in diametricallyopposite positions in the central part of the side wall of said sleeve(4), said central tongues (4) being provided with respective teeth (49)protruding inward to engage in respective longitudinal grooves (32)provided in said sheath (3).
 18. A safety syringe according to claim 17,wherein each of said longitudinal grooves (32) in the sheath (3) has arear abutment surface (33) which abuts against the respective tooth (49)of the central tongues of the sheath when said sheath (4) is in theretracted use position and a front abutment surface (34) that abutsagainst the respective tooth (49) when said sleeve (4) is in theadvanced safety position.
 19. A safety syringe (100) according to claim12, wherein said stop means comprise a pair of flexible rear tongues(50), longitudinally provided in diametrically opposite positions in arear part of the side wall of said sleeve, said central tongues (50)being inwardly convergent and having an abutment surface (52) able toabut against the front end of said sheath (3), when the sleeve (4) is insaid advanced safety position.
 20. A safety syringe (100) according toclaim 19, wherein each of said central tongues (47) and each of saidfront tongues (50) is defined by a respective substantially U-shapednotch (48, 51) formed respectively in the central part and in the frontpart of the side wall of said sleeve.
 21. A safety kit comprising asheath (3), a spring (6), a sleeve (4) and an operating means (22), tobe applied to a syringe to make it a safety syringe.
 22. A safety kitaccording to claim 21 wherein: said sheath (3) is integrally mounted onthe syringe body (1), said sleeve (4) is slidably mounted on said sheath(3) to pass from a retracted use position in which a needle (11) mountedon the front end of the syringe body (1) protrudes forward from saidsleeve to be able to perform the injection, to an advanced safetyposition in which the needle (11) is protected by said sleeve (4), saidspring (6) is interposed to act between said sleeve (4) and said sheath(3), said operating means are integrally mountable to the rear part of aplunger stem (20) of the syringe, locking and stop means being mutuallyprovided in said sheath (3) and in said sleeve (4) to lock said sleevein position when it is in said retracted use position and said advancedsafety position, said operating means cooperating with said lockingmeans, when the plunger is at the end of the injection stroke to allowmovement of said sleeve (4) from the retracted use position to theadvanced safety position.
 23. A safety kit according to claim 22,wherein said locking means comprise two teeth (31) radially protrudingfrom said sheath, in diametrically opposite directions, to engage inrespective slots (44) provided in two rear elastic tongues (43)longitudinally formed in the rear part of the side wall of said sleeve(4).
 24. A safety kit according to claim 22, wherein said operatingmeans comprise a frusto conical block (22) cooperating with said reartongues (43), when the plunger (2) reaches the end of the injectionstroke, in order to make them diverge outward to disengage said teeth(31) of the sheath from said slots (44) of the rear tongues
 25. A safetykit according to claim from 22, wherein said stop means comprise a pairof flexible central tongues (47), longitudinally provided indiametrically opposite positions in the central part of the side wall ofsaid sleeve (4), said central tongues (4) being provided with respectiveteeth (49) protruding inward to engage in respective longitudinalgrooves (32) provided in said sheath (3).
 26. A safety kit according toclaim 25, wherein each of said longitudinal grooves (32) in the sheath(3) has a rear abutment surface (33) which abuts against the respectivetooth (49) of the central tongues of the sheath when said sheath (4) isin the retracted use position and a front abutment surface (34) thatabuts against the respective tooth (49) when said sleeve (4) is in theadvanced safety position.
 27. A safety kit according to claim 22,wherein said stop means comprise a pair of flexible front tongues (50),longitudinally provided in diametrically opposite positions in a frontpart of the side wall of said sleeve, said front tongues (50) beinginwardly convergent and having an abutment surface (52) able to abutagainst the front end of said sheath (3), when the sleeve (4) is in saidadvanced safety position.